Evidence of direct correlation between out-of-plane lattice parameter and metal-insulator transition temperature in oxygen-depleted manganite thin films

We report on the role of oxygen content alone on structural and transport properties of La0.65Sr0.35MnO3−δ (LSMO) thin films. Identical films were deposited side-by-side during a single deposition run and subsequently post-annealed separately in vacuum to systematically vary the oxygen content. All films remained coherently strained to the SrTiO3 substrate, with no broadening of rocking curve widths after post-anneal. As oxygen content decreases, the LSMO unit cell expands while the metal-insulator transition temperature TMI decreases. A linear correlation between the out-of-plane lattice parameter and the metal-insulator transition temperature was observed.